Rocker arm covers are commonly utilized for combustion engine applications. The covers arc engaged sealably over a cylinder head of a combustion engine thereby protecting a series of rocker arms. The covers not only protect the rocker arms, but assure that oil, which sprays about and lubricates the rocker arms and surrounding mechanisms, remains within the engine cylinder head. The rocker arm cover typically is of a one piece construction having a resilient seal placed between the engine cylinder head and the rocker arm cover.
The high-pressure fuel injection system of a diesel combustion engine has a unique configuration compared to that of a gasoline engine. The high-pressure fuel injectors are commonly placed above and parallel to each combustion cylinder and can be accessed after removal of the rocker arm cover. The fuel injectors are fed by high-pressure fuel lines which penetrate a side of the engine cylinder head and engage the fuel injectors perpendicularly at mid-length. This engagement produces numerous problems. First, unwanted lateral stresses are placed upon the injectors which hinder reliability of radially extending injector seals. Second, fuel leakage at the injector connection is not easily detectable. Any leaking fuel can mix with the lubricating oil thereby compounding problems with engine operation.
To resolve these concerns, current interest is to extend the diesel fuel injectors up through the rocker arm cover. Fuel can then be fed to the injectors from a protruding injector end disposed above the rocker arm cover. The high-pressure fuel line connection to the injector is more reliable than the mid-length connection. And, any chance occurrence of fuel leakage is isolated from the engine oil and is easily detectable. Unfortunately, the high-pressure fuel lines must extend over the rocker arm cover to feed the fuel injectors. In order to service the rocker arms or mechanisms beneath the rocker arm cover, the high-pressure fuel lines must be dismantled prior to removing the rocker arm cover.